A Hexabenzocoronene-Based Helical Nanographene.

A synthetic route towards a novel hexabenzocoronene-based helical nanographene motif was developed. A hexaphenylbenzene precursor was therefore designed, which cannot undergo, due to steric restrictions, a complete planarization reaction. This precursor was transformed under oxidative cyclodehydrogenation conditions to a π-extended [5]helicene, which was fully characterized including X-ray diffraction analysis.

Multiple-Porphyrin Functionalized Hexabenzocoronenes.

Porphyrin-hexabenzocoronene architectures serve as good model compounds to study light-harvesting systems. Herein, the synthesis of porphyrin functionalized hexa-peri-hexabenzocoronenes (HBCs), in which one or more porphyrins are covalently linked to a central HBC core, is presented. A series of hexaphenylbenzenes (HPBs) was prepared and reacted under oxidative coupling conditions. The transformation to the respective HBC derivatives worked well with mono- and tri-porphyrin-substituted HPBs. However, if more porphyrins are attached to the HPB core, Scholl oxidations are hampered or completely suppressed. Hence, a change of the synthetic strategy was necessary to first preform the HBC core, followed by the introduction of the porphyrins. All products were fully characterized, including, if possible, single-crystal XRD. UV/Vis absorption spectra of porphyrin-HBCs showed, depending on the number of porphyrins as well as with respect to the substitution pattern, variations in their spectral features with strong distortions of the porphyrins' B-band.

Electronic Communication across Porphyrin Hexabenzocoronene Isomers.

Single-molecule electronic components (SMECs) are envisioned as next-generation building blocks in quantum circuit systems. However, challenges such as the reproducibility of the electrode attachment to the individual molecules hamper their fundamental investigation. For our purpose, we introduced quasi optoelectronic electrodes (QOEs) that allow for rapid investigations of the properties and suitability of compounds for molecular electronic devices. In particular, we probed hexa-peri-hexabenzocoronene (HBC) as a model system for D6h -symmetrical nanographenes, with porphyrins as QOEs attached to the periphery. We prepared selectively bis-porphyrin-functionalized HBCs with ortho-, meta- and para-substitution and studied their communication properties, in correlation to the geometrical alignment and size of the system, by electrochemistry and optical spectroscopy. Further insights into structure-property relationships were gained by DFT calculations and X-ray diffraction analysis.

Porphyrin-Hexaphenylbenzene Conjugates via Mixed Cyclotrimerization Reactions.

Mixed cyclotrimerization reactions of diarylacetylenes (tolans) were applied to generate a library of multiple porphyrin-hexaphenylbenzene (HPB) architectures. Successful reactions, which could be influenced by the ratio of tolan starting materials, were conducted using dicobaltoctacarbonyl as a catalyst. Separation of the reaction products was performed by chromatographic and crystallization techniques. The physical properties were investigated with respect to the number of porphyrins per HPB and their substitution pattern.

Interprofessional Collaborative Practice: How Could Dentistry Participate?

There is a remarkable phenomenon occurring among health professionals: the development of ongoing, routine collaboration, both in educating the next generation of providers and in delivering care. These new approaches, commonly referred to as interprofessional education and interprofessional collaborative practice, have been introduced into academic health settings and delivery systems throughout the U.S. and the rest of the world; however, the full integration of dentistry in health care teams remains unrealized. In academic settings, dentistry has found ways to collaborate with the other health professions, but most practicing dentists still find themselves on the margins of new models of care delivery. This article provides a perspective on the history and context of the evolution of collaborative approaches to health care and proposes ways in which dentistry can participate more fully in the future.

A Strategy towards the Multigram Synthesis of Uncommon Hexaarylbenzenes.

A novel rational synthetic pathway-the "functionalization of para-nitroaniline" (FpNA)-provides substituted hexaarylbenzenes (HABs) with uncommon symmetries that bear up to five different substituents, fully avoiding regioisomeric product distributions during the reactions. 4-Nitroaniline is functionalized by a cascade of electrophilic halogenations, Sandmeyer brominations, and Suzuki cross-coupling reactions, leading to 26 substitution geometries, of which 18 structures are not available by the current established techniques. Furthermore, we demonstrate that this method is applicable to the bulk production of such systems on a multigram scale. Regarding optoelectronic properties, we demonstrate how highly functionalized HABs can show strong luminescent behavior, making these molecules very attractive to organic electronic devices.

Will Large DSO-Managed Group Practices Be the Predominant Setting for Oral Health Care by 2025? Two Viewpoints: Viewpoint 1: Large DSO-Managed Group Practices Will Be the Setting in Which the Majority of Oral Health Care Is Delivered by 2025 and Viewpoint 2: Increases in DSO-Managed Group Practices Will Be Offset by Models Allowing Dentists to Retain the Independence and Freedom of a Traditional Practice.

This Point/Counterpoint article discusses the transformation of dental practice from the traditional solo/small-group (partnership) model of the 1900s to large Dental Support Organizations (DSO) that support affiliated dental practices by providing nonclinical functions such as, but not limited to, accounting, human resources, marketing, and legal and practice management. Many feel that DSO-managed group practices (DMGPs) with employed providers will become the setting in which the majority of oral health care will be delivered in the future. Viewpoint 1 asserts that the traditional dental practice patterns of the past are shifting as many younger dentists gravitate toward employed positions in large group practices or the public sector. Although educational debt is relevant in predicting graduates' practice choices, other variables such as gender, race, and work-life balance play critical roles as well. Societal characteristics demonstrated by aging Gen Xers and those in the Millennial generation blend seamlessly with the opportunities DMGPs offer their employees. Viewpoint 2 contends the traditional model of dental care delivery-allowing entrepreneurial practitioners to make decisions in an autonomous setting-is changing but not to the degree nor as rapidly as Viewpoint 1 professes. Millennials entering the dental profession, with characteristics universally attributed to their generation, see value in the independence and flexibility that a traditional practice allows. Although DMGPs provide dentists one option for practice, several alternative delivery models offer current dentists and future dental school graduates many of the advantages of DMGPs while allowing them to maintain the independence and freedom a traditional practice provides.

Continued Competency Assessment. Its history and role in the health professions.

The concept of an implicit contract between the public and a profession is used as a foundation for the responsibility for professions to develop continued competency assessment and enforcement mechanisms that ensure that the public can expect safe and competent care. The literature in medicine, other health professions, and from other countries is reviewed. There is concern that the fact of continued practice alone does not ensure continued competency in a changing profession and that mandatory continuing education attendance is insufficient. Public-interest groups that have looked at the issue report greater concern among the public than in the professions that effective continued competency mechanism be established and that action be taken where practitioners who are not competent are identified. There has been substantial develop of a variety of approaches in medicine, especially through the specialty boards which account for the majority of medical practitioners, in other health fields, and in several countries.

Continued Competency Assessment. Does it have a necessary role in dentistry?

The responsibility of regulating dental practice in the interest of public safety is vested in the states and is exercised through delegated initial competency evaluation of new graduates, continuing education attendance requirements, and investigations of complaints. Questions have been raised over whether this model can demonstrate effectiveness and whether it ensures continuous professional growth or only identifies the clearly incompetent. There have been reports identifying desireable standards and there are pilot programs for continued competency in dentistry. These are reviewed. A set of criteria for any effective program is presented.